**EXHIBIT 4.12**SEVENTH AMENDMENT TO CREDIT AGREEMENT     THIS SEVENTH AMENDMENT TO CREDIT AGREEMENT (this “Seventh Amendment”), dated as ofAugust 12, 2005, is entered into among ELKCORP (formerly known as Elcor Corporation), a Delawarecorporation (the “Borrower”), the lenders listed on the signature pages hereof as Lenders(the “Lenders”), BANK ONE, N.A., as Documentation Agent, and BANK OF AMERICA, N.A., asAdministrative Agent, Swing Line Lender and L/C Issuer.BACKGROUND     A. The Borrower, certain of the Lenders, the Documentation Agent, the Syndication Agent, theAdministrative Agent, the Swing Line lender and the L/C Issuer are parties to that certain CreditAgreement, dated as of November 30, 2000, as amended by that certain First Amendment to CreditAgreement, dated as of March 31, 2001, that certain Second Amendment to Credit Agreement, dated asof June 5, 2002, that certain Third Amendment to Credit Agreement, dated as of February 20, 2003,that certain Fourth Amendment to Credit Agreement, dated as of March 7, 2003, that certain FifthAmendment to Credit Agreement, dated as of December 5, 2003, and that certain Sixth Amendment toCredit Agreement, dated as of May 27, 2005 (said Credit Agreement, as amended, the “CreditAgreement”). The terms defined in the Credit Agreement and not otherwise defined herein shallbe used herein as defined in the Credit Agreement.     B. The Borrower has requested certain amendments to the Credit Agreement.     C. The Lenders, the Documentation Agent, the Administrative Agent, the Swing Line Lender andthe L/C Issuer hereby agree to amend the Credit Agreement, subject to the terms and conditions setforth herein.     NOW, THEREFORE, in consideration of the covenants, conditions and agreements hereafter setforth, and for other good and valuable consideration, the receipt and adequacy of which are allhereby acknowledged, the Borrower, the Lenders, the Swing Line Lender, the L/C Issuer and theAdministrative Agent covenant and agree as follows:     1. AMENDMENTS.     (a) The definition of “Permitted Investment” set forth in Section 1.01 of theCredit Agreement is hereby amended by amending clause (h) thereof to read as follows:     (h) Investments in any Guarantor, including any Person that simultaneouslybecomes a Guarantor at the time of the initial Investment therein;     (b) Section 7.01 of the Credit Agreement is hereby amended by (i) deleting “and” afterclause (g) thereof, (ii) deleting “.” after clause (h) thereof and inserting “; and” in lieuthereof and (iii) adding a new clause (i) thereto to read as follows:
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     (i) Liens (i) securing Indebtedness in respect of capital leases and purchasemoney obligations for fixed or capital assets, provided that (A) such Liensdo not at any time encumber any property other than the property financed by suchIndebtedness and (B) the Indebtedness secured thereby does not exceed the cost orfair market value, whichever is lower, of the property being acquired on the date ofacquisition and (ii) encumbering property acquired in a Permitted Investment,provided that (A) such Liens were already in existence prior to the date ofsuch Permitted Investment and were not created in contemplation of or in connectionwith such Permitted Investment, (B) such Liens do not at any time encumber anyproperty other than property theretofore encumbered by such Liens and (C) theIndebtedness secured thereby (other than interest accruing thereon in accordancewith its terms) does not exceed the amount secured on the date of such PermittedInvestment; provided further, however, the aggregate principal amount ofIndebtedness secured by Liens permitted pursuant to both of clauses (i) and (ii)immediately preceding shall not exceed $25,000,000 at any time.     (c) Exhibit E to the Credit Agreement, the Compliance Certificate, is hereby amendedto be in the form of Exhibit E to this Seventh Amendment.     2. REPRESENTATIONS AND WARRANTIES TRUE; NO EVENT OF DEFAULT. By its execution anddelivery hereof, the Borrower represents and warrants that, as of the date hereof:     (a) the representations and warranties contained in the Credit Agreement and the other LoanDocuments are true and correct on and as of the date hereof as made on and as of such date;     (b) no event has occurred and is continuing which constitutes a Default or an Event ofDefault;     (c) (i) the Borrower has full power and authority to execute and deliver this SeventhAmendment, (ii) this Seventh Amendment has been duly executed and delivered by the Borrower, and(iii) this Seventh Amendment and the Credit Agreement, as amended hereby, constitute the legal,valid and binding obligations of the Borrower, enforceable in accordance with their respectiveterms, except as enforceability may be limited by applicable debtor relief laws and by generalprinciples of equity (regardless of whether enforcement is sought in a proceeding in equity or atlaw) and except as rights to indemnity may be limited by federal or state securities laws;     (d) neither the execution, delivery and performance of this Seventh Amendment or the CreditAgreement, as amended hereby, nor the consummation of any transactions contemplated herein ortherein, will conflict with any Law or Organization Documents of the Borrower, or any indenture,agreement or other instrument to which the Borrower or any of its property is subject; and
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     (e) no authorization, approval, consent, or other action by, notice to, or filing with, anygovernmental authority or other Person not previously obtained is required for the execution,delivery or performance by the Borrower of this Seventh Amendment.     3. CONDITIONS TO EFFECTIVENESS. This Seventh Amendment shall be effective uponsatisfaction or completion of the following:     (a) the Administrative Agent shall have received counterparts of this Seventh Amendmentexecuted by the Required Lenders;     (b) the Administrative Agent shall have received counterparts of this Seventh Amendmentexecuted by the Borrower and acknowledged by each Guarantor; and     (c) the Administrative Agent shall have received, in form and substance satisfactory to theAdministrative Agent and its counsel, such other documents, certificates and instruments as theAdministrative Agent shall require.     4. REFERENCE TO THE CREDIT AGREEMENT.     (a) Upon the effectiveness of this Seventh Amendment, each reference in the Credit Agreementto “this Agreement”, “hereunder”, or words of like import shall mean and be a reference to theCredit Agreement, as affected and amended hereby.     (b) The Credit Agreement, as amended by the amendments referred to above, shall remain in fullforce and effect and is hereby ratified and confirmed.     5. COSTS, EXPENSES AND TAXES. The Borrower agrees to pay on demand all costs andexpenses of the Administrative Agent in connection with the preparation, reproduction, executionand delivery of this Seventh Amendment and the other instruments and documents to be deliveredhereunder (including the reasonable fees and out-of-pocket expenses of counsel for theAdministrative Agent with respect thereto).     6. GUARANTOR’S ACKNOWLEDGMENT. By signing below, each Guarantor (a) acknowledges,consents and agrees to the execution, delivery and performance by the Borrower of this SeventhAmendment, (b) acknowledges and agrees that its obligations in respect of its Guaranty (i) are notreleased, diminished, waived, modified, impaired or affected in any manner by this SeventhAmendment or any of the provisions contemplated herein, (c) ratifies and confirms its obligationsunder its Guaranty, and (d) acknowledges and agrees that it has no claims or offsets against, ordefenses or counterclaims to, its Guaranty.     7. EXECUTION IN COUNTERPARTS. This Seventh Amendment may be executed in any number ofcounterparts and by different parties hereto in separate counterparts, each of which when soexecuted and delivered shall be deemed to be an original and all of which when taken together shallconstitute but one and the same instrument. For purposes of this Seventh Amendment, a counterparthereof (or signature page thereto) signed and transmitted by any Person party hereto to theAdministrative Agent (or its counsel) by facsimile machine, telecopier or electronic mail is to betreated as an original. The signature of such Person thereon,
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for purposes hereof, is to be considered as an original signature, and the counterpart (orsignature page thereto) so transmitted is to be considered to have the same binding effect as anoriginal signature on an original document.     8. GOVERNING LAW; BINDING EFFECT. This Seventh Amendment shall be governed by andconstrued in accordance with the laws of the State of Texas applicable to agreements made and to beperformed entirely within such state, provided that each party shall retain all rights arisingunder federal law, and shall be binding upon the parties hereto and their respective successors andassigns.     9. HEADINGS. Section headings in this Seventh Amendment are included herein forconvenience of reference only and shall not constitute a part of this Seventh Amendment for anyother purpose.     10. ENTIRE AGREEMENT. THE CREDIT AGREEMENT, AS AMENDED BY THIS SEVENTH AMENDMENT, ANDTHE OTHER LOAN DOCUMENTS REPRESENT THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BECONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS BETWEEN THEPARTIES. THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.
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     IN WITNESS WHEREOF, this Seventh Amendment is executed as of the date first set forth above.       **ELKCORP**       By:           Gregory J. Fisher    Senior Vice President, Chief Financial Officerand Controller
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         **BANK OF AMERICA, N.A.**, as Administrative Agent         By:             Name:             Title:         
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         **BANK OF AMERICA, N.A**., as a Lender, L/C Issuer andSwing Line Lender         By:             Name:             Title:         
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         **JPMORGAN CHASE BANK, N.A.**, as a Lender andDocumentation Agent         By:             Name:             Title:         
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         **THE NORTHERN TRUST COMPANY**, as a Lender         By:             Name:             Title:         
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         **WELLS FARGO BANK, NATIONAL ASSOCIATION**, as a Lender         By:             Name:             Title:         
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         **COMPASS BANK**, as a Lender         By:             Name:             Title:         
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         **HIBERNIA NATIONAL BANK**, as a Lender         By:             Name:             Title:         
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         **BRANCH BANKING AND TRUST COMPANY**, as a Lender         By:             Name:             Title:         
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         **KEYBANK NATIONAL ASSOCIATION**, as a Lender         By:             Name:             Title:         
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ACKNOWLEDGED AND AGREED TO:ELK PREMIUM BUILDING PRODUCTS, INC.